1. Technical Field
The present invention relates to a depository monitoring system and, more particularly, to a depository monitoring system integrated with radio frequency identification (RFID) techniques.
2. Description of Related Art
Prior art in relation to wafer inventory or transport using RFID techniques are disclosed in U.S. Pat. No. 6,330,971 (hereinafter referred to as '971), U.S. Patent Application Publication No. 20060043197 (hereinafter referred to as '197) and Taiwan Patent No. 1267029 (hereinafter referred to as '029). The '971 patent provides a wafer tracking system using RFID techniques, as shown in FIG. 1A, in which a system 10 comprises a plurality of wafer-carried carriers 11, an RFID reader 12, an RFID tag 14 mounted on each of the carriers 11, and a controller 13. The RFID reader 12 reads the RFID tag 14 mounted on each of the carriers 11 through a plurality of antennas 15 connected thereto, and then sends a tag information read from the RFID tag 14 to the controller 13 via an RS-232 interface, thereby providing information regarding present locations of the carriers 11 and wafers carried thereon.
The '197 patent application provides a wafer transport system using a carrier integrated with RFID techniques, as shown in FIG. 1B, in which a system 100 comprises a transport device 110, a carrier 111 for carrying wafers, a processing tool 115, an RFID reader 116 and a tool controller 117. When the carrier 111 is transported to the processing tool 115 by the transport device 110, the RFID reader 116 which is mounted on the processing tool 115 reads an RFID tag 114 mounted on a carrier body 112 for sending a carrier identification code stored in the RFID tag 114 to the tool controller 117; thereby performing the processing tool 115 to process wafers in the carrier 111.
The '029 patent provides a wafer transport system using a carrier integrated with RFID techniques, as shown in FIG. 1C, in which a transport system 1000 comprises a wafer cassette 1010, an RFID tag 1020 attached to the wafer cassette 1010, a transport device 1030, a processing tool 1040, an RFID reader 1050, a host 1060 and a trigger 1070. When the RFID tag 1020 of the wafer cassette 1010 appears in the vicinity of the processing tool 1040, an RFID interrogator can directly retrieve information from the RFID tag 1020 and automatically activate the transport device 1030. As a result, the wafer cassette 1010 may be mistakenly transported to a port by a mechanical arm, thereby injuring an operator. However, the operator can give instructions to the host 1060 by directly operating the trigger 1070, so as to control the timing of information retrieval by the RFID interrogator. Therefore, the mechanical arm will not be accidentally activated by untimely retrieval of information from the RFID tag 1020 by the RFID interrogator, and the operator's safety is thus secured.
While the prior art mentioned above uses RFID techniques to transport or track wafers, the RFID techniques are not effectively integrated with an information system for depository monitoring. As a result, a wafer-based depository cannot be monitored in real time by the operator. Therefore, it is a pressing issue in relevant industries to integrate RFID techniques into an information system for depository monitoring, so that the operator can perform on-line and real-time management of a depository of semiconductor products and a semiconductor testing schedule.